High voltage metal oxide semiconductor (MOS) transistors which operate at drain voltages higher than the maximum operating voltages of the gate dielectric layers of the transistors frequently include drift regions in the drains of the transistors. The drift regions provide voltage drops from the drain contact to the drain portion adjacent to the transistor channel regions, thereby reducing the voltages across the gate dielectric layers to values within the maximum operating voltages of the gate dielectric layers. Drift regions commonly have doping densities less than drain contact regions, and so undesirable increase the series resistances of the transistors.